Aluminum alloy products with hot melt laminate coating for electrical insulation

Abstract

Described herein is an electrically insulated metal product and a method for preparing the electrically insulated metal product. The electrically insulated metal product can include a multi-layered polymer insulating structure, which includes an adhesive layer and a top polymer layer, which are disposed on a metal-based layer to provide electrical insulation for the metal-based layer, for example, by using a process of laminating a polymer film on the metal-based layer. The multi-layered polymer insulating structure and the metal-based layer can be subjected to annealing after lamination to improve adhesion performance.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 362,937, filed April 13, 2022, entitled "ALUMINUM ALLOY PRODUCTS WITH HOT-MELT LAMINATION COATINGS FOR ELECTRICAL INSULATION," the contents of which are incorporated herein by reference in their entirety.

[0002] The present disclosure relates generally to metallurgy, and more specifically to electrically insulated aluminum alloy products. [Background technology]

[0003] Metallic products are routinely used as structural enclosures for all kinds of products, devices, and systems. Steel enclosures are commonly used where high strength is required, with aluminum enclosures also being used in some applications. Summary of the Invention

[0004] The terms embodiments and similar terms are intended to broadly refer to the subject matter of this disclosure and all of the claims that follow. Statements containing these terms should be understood to neither limit the subject matter described herein nor limit the meaning or scope of the claims that follow. The embodiments of the disclosure addressed herein are defined by the claims that follow, and not by this summary. This summary is a high-level overview of various aspects of the disclosure and introduces some of the ideas that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification of this disclosure, any or all drawings, and appropriate portions of each claim.

[0005] Aluminum is significantly less dense than steel, but can provide high strength properties, making it useful for many applications. Its use in structural components (e.g., enclosures for electronic devices) can provide high strength at a low weight compared to steel. Like steel, aluminum is a conductive material, so the use of such materials in enclosures for electronic devices can benefit from electrical insulation between the electronic device and the enclosure, such as reducing the risk of short circuits or other undesirable effects.

[0006] This disclosure describes an aluminum substrate with a multilayer polymer insulating structure bonded, bonded, or otherwise coupled to its surface. In some examples, the multilayer polymer insulating structure is or can include a polymer film disposed on the aluminum substrate with an adhesive layer. In some examples, the multilayer polymer insulating structure is or can include a polymer film and an adhesive layer bonding the polymer film to the aluminum substrate. In such examples, the polymer film can be attached to the aluminum substrate using an adhesive layer therebetween. In other examples, the multilayer polymer insulating structure can be or can include a polymer multilayer film disposed directly on the aluminum substrate and bonded to the aluminum substrate. Bonding is performed using a hot melt lamination process, such as a process in which the lower melting temperature polymer layer of the polymer multilayer film is heated near, at, or above its melting temperature to allow for intimate contact between the lower melting temperature polymer layer and the aluminum substrate. Using these techniques, the multilayer polymer insulating structure can be attached to the aluminum substrate as a composite structure to impart insulating properties to the composite structure.

[0007] In some examples, the present disclosure provides an electrically insulated metal article including an aluminum alloy sheet metal substrate and a multilayer polymeric insulating structure bonded to the aluminum alloy sheet metal substrate. Optionally, the multilayer polymeric insulating structure includes a bonding layer adjacent to the aluminum alloy sheet metal substrate and a top polymer layer on the bonding layer. Optionally, the multilayer polymeric insulating structure has a thickness of 5 μm to 100 μm. Optionally, the multilayer polymeric insulating structure bonded to the aluminum alloy sheet metal substrate has an overall surface resistivity of 1×10 12 Ω~1×10 15 Ω, volume resistivity is 1×10 12 Ω~1×10 15 Ω, a breakdown voltage between 2 kV and 50 kV, or a comparative tracking index value between 175 V and 400 V.

[0008] In one aspect, the present disclosure provides a method for preparing an electrically insulated metal product. An example method includes preheating an aluminum alloy sheet metal substrate to a first temperature of 150° C. to 250° C. and bonding a multi-layer polymer insulating structure to a surface of the aluminum alloy sheet metal substrate to produce a bonded product, the multi-layer polymer insulating structure including a bonding layer and a top polymer layer on the bonding layer. Optionally, the multilayer polymer insulating structure has a thickness of 5 μm to 100 μm, e.g., 5 μm to 10 μm, 10 μm to 15 μm, 15 μm to 20 μm, 20 μm to 25 μm, 25 μm to 30 μm, 30 μm to 35 μm, 35 μm to 40 μm, 40 μm to 45 μm, 45 μm to 50 μm, 50 μm to 55 μm, 55 μm to 60 μm, 60 μm to 65 μm, 65 μm to 70 μm, 70 μm to 75 μm, 75 μm to 80 μm, 80 μm to 85 μm, 85 μm to 90 μm, 90 μm to 95 μm, or 95 μm to 100 μm.

[0009] Optionally, the multi-layer polymer insulating structure bonded to the aluminum alloy sheet metal substrate has a surface resistance of less than 1×10 12 Ω~1×10 15 Ω, volume resistivity is 1×10 12 Ω~1×10 15 Ω, a breakdown voltage between 2 kV and 50 kV, or a comparative tracking index value between 175 V and 400 V. In an example, a multilayer polymer insulation structure bonded to an aluminum alloy sheet metal substrate has, overall, a surface resistance of 1×10 12 Ω~5×10 12 Ω, 5×10 12 Ω~1×10 13 Ω, 1×10 13 Ω~5×10 13 Ω, 5×10 13 Ω~1×10 14 Ω, 1×10 14 Ω~5×10 14 Ω, or 5×10 14 Ω~1×10 15In examples, the multilayer polymeric insulating structure bonded to an aluminum alloy sheet metal substrate generally exhibits a breakdown voltage of 2 kV to 5 kV, 5 kV to 10 kV, 10 kV to 15 kV, 15 kV to 20 kV, 20 kV to 25 kV, 25 kV, 30 kV, 30 kV to 35 kV, 35 kV to 40 kV, 40 kV to 45 kV, or 45 kV to 50 kV. In an example, a multilayer polymer insulation structure bonded to an aluminum alloy sheet metal substrate, as a whole, has comparative tracking index values ​​of 175V-180V, 180V-185V, 185V-190V, 190V-195V, 195V-200V, 200V-205V, 205V-210V, 200V-205V, 205V-210V, 210V-215V, 215V-220V, 220V-225V, 225V-230V, 230V-235V, 235V-240V, 240V-245V, 245V-250V, 250V-255V, 255V-260V, 260V-265V, 265V-270V, 270V-275V, 275V~280V, 280V~285V, 285V~290V, 290V~295V, 295V~300V, 300V~305V, 305V~310V , 300V~305V, 305V~310V, 310V~315V, 315V~320V, 320V~325V, 325V~330V, 330V~335 V, 335V~340V, 340V~345V, 345V~350V, 350V~355V, 355V~360V, 360V~365V, 365V~370V, 370V~375V, 375V~380V, 380V~385V, 385V~390V, 390V~395V, or 395V~400V.

[0010] Optionally, the bonding layer comprises a first polyester film and the top polymer layer comprises a second polyester film having a different composition than the first polyester film. Optionally, the bonding layer comprises a polymer sealing layer exhibiting a first melting temperature and the top polymer layer exhibits a second melting or decomposition temperature higher than the first melting temperature. Optionally, the top polymer layer comprises polyethylene, polypropylene, and / or polyethylene terephthalate.

[0011] Optionally, the first melting temperature is between 150°C and 250°C, e.g., between 150°C and 155°C, between 155°C and 160°C, between 160°C and 165°C, between 165°C and 170°C, between 170°C and 175°C, between 175°C and 180°C, between 180°C and 185°C, between 185°C and 190°C, between 190°C and 195°C, between 195°C and 200°C, between 205°C and 210°C, between 210°C and 215°C, between 215°C and 220°C, between 220°C and 225°C, between 225°C and 230°C, between 230°C and 235°C, between 235°C and 240°C, between 240°C and 245°C, or between 245°C and 250°C.

[0012] Optionally, bonding includes subjecting the multilayer polymeric insulating structure and the aluminum alloy sheet metal substrate to lamination conditions including exposure to a lamination temperature of 175°C to 300°C and / or exposure to a lamination pressure of 1 bar to 7 bar. Optionally, the lamination temperature is 175°C to 180°C, 180°C to 185°C, 185°C to 190°C, 190°C to 195°C, 195°C to 200°C, 200°C to 205°C, 205°C to 210°C, 210°C to 215°C, 215°C to 220°C, 220°C to 225°C, 225°C to 230°C, 230°C to 235 ... 5℃~240℃, 240℃~245℃, 245℃~250℃, 250℃~255℃, 255℃~260℃, 260℃~265℃, 265℃~270℃, 270℃~275℃, 275℃~280℃, 280℃~285℃, 285℃~290℃, 290℃~295℃, or 295℃~300℃. Optionally, the lamination pressure is between 1 bar and 1.5 bar, between 1.5 bar and 2 bar, between 2 bar and 2.5 bar, between 2.5 bar and 3 bar, between 3 bar and 3.5 bar, between 3.5 bar and 4 bar, between 4 bar and 4.5 bar, between 4.5 bar and 5 bar, between 5 bar and 5.5 bar, between 5.5 bar and 6 bar, between 6 bar and 6.5 bar, or between 6.5 bar and 7 bar.

[0013] Optionally, the method of this embodiment further comprises annealing the bonded product at an annealing temperature between 175° C. and 300° C., e.g., between 175° C. and 180° C., between 180° C. and 185° C., between 185° C. and 190° C., between 190° C. and 195° C., between 195° C. and 200° C., between 205° C. and 210° C., between 210° C. and 215° C., between 215° C. and 220° C., between 220° C. and 225° C., between 225° C. and 230° C., or between 230° C. and 230° C. It may include performing the reaction at 0°C, 230°C to 235°C, 235°C to 240°C, 240°C to 245°C, 245°C to 250°C, 250°C to 255°C, 255°C to 260°C, 260°C to 265°C, 265°C to 270°C, 270°C to 275°C, 275°C to 280°C, 280°C to 285°C, 285°C to 290°C, 290°C to 295°C, or 295°C to 300°C.

[0014] Optionally, the multi-layer polymeric insulating structure is bonded to a surface of the aluminum alloy sheet metal substrate without the use of an adhesive layer between the aluminum alloy sheet metal substrate and the multi-layer polymeric insulating structure. Optionally, no adhesive layer is disposed between the aluminum alloy sheet metal substrate and the multi-layer polymeric insulating structure. Optionally, the bonding layer comprises an adhesive layer between the aluminum alloy sheet metal substrate and the top polymer layer.

[0015] For example, in some cases, an adhesive layer is disposed on the aluminum alloy sheet metal substrate prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer, or an adhesive layer is disposed on the top polymer layer prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer.

[0016] Optionally, the aluminum alloy sheet metal substrate includes a surface pretreatment coating on the aluminum alloy sheet metal base layer. For example, in some cases, the surface pretreatment coating includes a Ti-Zr based conversion coating, a Cr based conversion coating, or a copolymer based coating.

[0017] Optionally, the method of this aspect may further include subjecting the bonded product to one or more forming processes to produce a formed product. Example processes include, but are not limited to, stamping, roll forming, etc.

[0018] In some examples, the present disclosure provides a structural enclosure for a device, such as an electronic device. The example structural enclosure includes an electrically insulated metal fabrication that includes an aluminum alloy sheet metal substrate and a multilayer polymeric insulating structure bonded to the aluminum alloy sheet metal substrate. Optionally, the multilayer polymeric insulating structure includes a bonding layer adjacent to the aluminum alloy sheet metal substrate and a top polymer layer on the bonding layer. Optionally, the multilayer polymer insulating structure has a thickness of 5 μm to 100 μm, such as 5 μm to 100 μm, for example 5 μm to 10 μm, 10 μm to 15 μm, 15 μm to 20 μm, 20 μm to 25 μm, 25 μm to 30 μm, 30 μm to 35 μm, 35 μm to 40 μm, 40 μm to 45 μm, 45 μm to 50 μm, 50 μm to 55 μm, 55 μm to 60 μm, 60 μm to 65 μm, 65 μm to 70 μm, 70 μm to 75 μm, 75 μm to 80 μm, 80 μm to 85 μm, 85 μm to 90 μm, 90 μm to 95 μm, or 95 μm to 100 μm.

[0019] Optionally, the multi-layer polymer insulating structure bonded to the aluminum alloy sheet metal substrate has a surface resistance of less than 1×10 12 Ω~1×10 15 Ω, volume resistivity is 1×10 12 Ω~1×10 15 Ω, a breakdown voltage between 2 kV and 50 kV, or a comparative tracking index value between 175 V and 400 V. In some instances, a multilayer polymeric insulating structure bonded to an aluminum alloy sheet metal substrate may, in its entirety, have a surface resistance of 1×10 12 Ω~5×10 12 Ω, 5×10 12 Ω~1×10 13 Ω, 1×10 13 Ω~5×10 13 Ω, 5×10 13Ω~1×10 14 Ω, 1×10 14 Ω~5×10 14 Ω, or 5×10 14 Ω~1×10 15 In some examples, the multilayer polymeric insulation structure bonded to an aluminum alloy sheet metal substrate as a whole exhibits a breakdown voltage of 2 kV to 5 kV, 5 kV to 10 kV, 10 kV to 15 kV, 15 kV to 20 kV, 20 kV to 25 kV, 25 kV, 30 kV, 30 kV to 35 kV, 35 kV to 40 kV, 40 kV to 45 kV, or 45 kV to 50 kV. In some examples, the multilayer polymeric insulation structure bonded to an aluminum alloy sheet metal substrate, as a whole, has a comparative tracking index value of 175V-180V, 180V-185V, 185V-190V, 190V-195V, 195V-200V, 200V-205V, 205V-210V, 200V-205V, 205V-210V, 210V-215V, 215V-220V, 220V-225V, 225V-230V, 230V-235V, 235V-240V, 240V-245V, 245V-250V, 250V-255V, 255V-260V, 260V-265V, 265V-270V, 270V-275V, and 275V-275V. V, 275V~280V, 280V~285V, 285V~290V, 290V~295V, 295V~300V, 300V~305V, 305V~31 0V, 300V~305V, 305V~310V, 310V~315V, 315V~320V, 320V~325V, 325V~330V, 330V~33 Indicates 5V, 335V~340V, 340V~345V, 345V~350V, 350V~355V, 355V~360V, 360V~365V, 365V~370V, 370V~375V, 375V~380V, 380V~385V, 385V~390V, 390V~395V, or 395V~400V.

[0020] Other objects and advantages will become apparent from the following detailed description of non-limiting examples.

[0021] This specification refers to the following accompanying drawings, in which the use of like reference numbers in different drawings is intended to indicate the same or similar components. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic diagram of an example electrically isolated metal article. [Diagram 2] 1 is a schematic overview of an example method for making a rolled aluminum alloy product. [Diagram 3] 1 is a schematic overview of an example method for making an electrically isolated metal article. [Figure 4] FIG. 1 is a schematic diagram of laminating a polymer insulating film to an aluminum alloy sheet metal substrate. [Diagram 5] FIG. 2 is a schematic exploded view of an example structural enclosure for a device. [Figure 6] 1 is a photograph of a sample of an electrically insulated metal product after being subjected to a comparative tracking index test. [Figure 7] 1 is a photograph of a sample of an electrically insulated metal product after being subjected to an adhesion performance test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Described herein are electrically insulated metal products and methods for making electrically insulated metal products. The metal products include an aluminum alloy sheet metal substrate with a coating or layer of a multilayer polymeric insulating film disposed on one or more surfaces. The metal products can be processed into any suitable shape or form, for example, by subjecting the electrically insulated metal products to molding, stamping, or other processing, so that structural enclosures (e.g., structural enclosures for electrical or electronic devices where electrical insulation may be desired to prevent contact or short circuit occurrence) can be prepared from the electrically insulated metal products.

[0024] The multilayer polymeric insulating film can include a sealing layer that allows the multilayer polymeric insulating film to be laminated to the surface of a base sheet metal substrate, for example, by subjecting the film to heat and / or pressure when applying the multilayer polymeric insulating film to the sheet metal substrate. The multilayer polymeric insulating film bonded to the base sheet metal substrate can exhibit or be characterized by electrical insulating properties, for example, a surface resistivity of 1×10 12 Ω~1×10 15 Ω, volume resistivity is 1×10 12 Ω~1×10 15 Ω, a breakdown voltage between 2 kV and 50 kV, and / or a comparative tracking index value between 175 V and 400 V. Such properties can be achieved using thin layers (e.g., between 5 μm and 100 μm thick) of multilayer polymeric insulating films.

[0025] 1 illustrates a schematic diagram of an example electrically isolated metal product 100. As shown, the electrically isolated metal product 100 includes an aluminum alloy sheet metal substrate 105 and a multilayer polymeric insulating film 110 disposed on the aluminum alloy sheet metal substrate 105. Although the multilayer polymeric insulating film 110 is only shown on the top surface of the aluminum alloy sheet metal substrate 105 in FIG. 1, examples are included in the present description in which both the top and bottom surfaces of the aluminum alloy sheet metal substrate include the multilayer polymeric insulating film.

[0026] The multilayer polymer insulating film 110 may include multiple different films or layers, for example attached, connected, or adjacent to each other. For example, a bonding layer 115 in contact with a surface of the aluminum alloy sheet metal substrate 105, and a top polymer layer 120 adjacent to the bonding layer 115. The bonding layer 115 and the top polymer layer 120 may include different materials or they may be the same. In some examples, the bonding layer may include a sealing layer. In some examples, the bonding layer 115 and the top polymer layer 120 include polyester layers (e.g., one or more of polyethylene, polypropylene, and / or polyethylene terephthalate). In some examples, the bonding layer 115 includes a first polyester film and the top polymer layer 120 includes a second polyester film having a different composition than the first polyester film. The bonding layer 115 may, for example, exhibit a lower melting temperature than the top polymer layer 120. In some examples, the sealing layer 115 may exhibit a melting temperature between 150°C and 250°C, e.g., between 150°C and 155°C, between 155°C and 160°C, between 160°C and 165°C, between 165°C and 170°C, between 170°C and 175°C, between 175°C and 180°C, between 180°C and 185°C, between 185°C and 190°C, between 190°C and 195°C, between 195°C and 200°C, between 205°C and 210°C, between 210°C and 215°C, between 215°C and 220°C, between 220°C and 225°C, between 225°C and 230°C, between 230°C and 235°C, between 235°C and 240°C, between 240°C and 245°C, or between 245°C and 250°C. Advantageously, the multilayer polymer insulating film 110 can be free of pinholes or other defects that provide a conductive path to the aluminum alloy sheet metal substrate 105. Optionally, the bonding layer 115 can include an adhesive layer. In some examples, the bonding layer 115 can be an adhesive layer that is applied to the aluminum alloy sheet metal substrate 105 prior to bonding with the top polymer layer 120. In other examples, the bonding layer 115 can be an adhesive layer that is applied to the top polymer layer 120 prior to bonding with the aluminum alloy sheet metal substrate 105. In some examples, useful adhesives include, without limitation, acrylic adhesives, polyester adhesives, or epoxy adhesives.

[0027] The aluminum alloy sheet metal substrate 105 may include any suitable aluminum alloy and may optionally include a surface pretreatment layer, anodization layer, or oxide surface layer. With the multilayer polymeric insulating film 110 disposed thereon, the aluminum alloy sheet metal substrate 105 may be subjected to forming or other processing to provide electrically insulated metal products in non-planar shapes (e.g., useful for creating device enclosures, etc.). Additionally, other electrically insulated metal products may be prepared from the aluminum alloy sheet metal substrate 105 and the multilayer polymeric insulating film 110.

[0028] Definitions and Explanations As used herein, the terms "invention," "the invention," "this invention," and "the present invention" are intended to refer broadly to all of the subject matter of this patent application and the claims that follow. Statements containing these terms should be understood in no way to limit the subject matter described herein or to limit the meaning or scope of the claims that follow.

[0029] In this description, reference is made to alloys identified by AA numbers and other associated designations (e.g., "Series" or "7xxx"). To understand the numbering systems most commonly used in naming and identifying aluminum and its alloys, please see "International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys," or "Registration Record of Aluminum Association Alloy Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot" (both published by The Aluminum Association).

[0030] As used herein, a plate generally has a thickness of greater than about 15 mm. For example, a plate may refer to an aluminum product having a thickness of greater than about 15 mm, greater than about 20 mm, greater than about 25 mm, greater than about 30 mm, greater than about 35 mm, greater than about 40 mm, greater than about 45 mm, greater than about 50 mm, or greater than about 100 mm.

[0031] As used herein, a shade (also called a sheet plate) generally has a thickness of about 4 mm to about 15 mm. For example, the shade may have a thickness of about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, or about 15 mm.

[0032] As used herein, sheet generally refers to an aluminum product having a thickness of less than about 4 mm. For example, the sheet may have a thickness of less than about 4 mm, less than about 3 mm, less than about 2 mm, less than about 1 mm, less than about 0.5 mm, or less than about 0.3 mm (e.g., about 0.2 mm).

[0033] In this application, alloy tempers or conditions may be referred to. To understand the description of the most commonly used alloy tempers, please refer to "American National Standards (ANSI) H35 on Alloy and Temper Designation Systems". The F state or temper refers to the aluminum alloy as produced. The O state or temper refers to the aluminum alloy after annealing. The Hxx state or temper (also referred to herein as the H temper) refers to the non-heat treated aluminum alloy after cold rolling, with or without heat treatment (e.g., annealing). Suitable H tempers include Hx1, Hx2, Hx3, Hx4, Hx5, Hx6, Hx7, Hx8, or Hx9 tempers. The T1 state or temper refers to the aluminum alloy that has been cooled from hot working and naturally aged (e.g., at room temperature). The T2 state or temper refers to the aluminum alloy that has been cooled from hot working, cold worked, and naturally aged. The T3 condition or temper refers to an aluminum alloy that has been solution heat treated, cold worked, and naturally aged. The T4 condition or temper refers to an aluminum alloy that has been solution heat treated and naturally aged. The T5 condition or temper refers to an aluminum alloy that has been cooled from hot working and artificially aged (at high temperature). The T6 condition or temper refers to an aluminum alloy that has been solution heat treated and artificially aged. The T7 condition or temper refers to an aluminum alloy that has been solution heat treated and artificially overaged. The T8x condition or temper refers to an aluminum alloy that has been solution heat treated, cold worked, and artificially aged. The T9 condition or temper refers to an aluminum alloy that has been solution heat treated, artificially aged, and cold worked. The W condition or temper refers to an aluminum alloy after solution heat treatment.

[0034] As used herein, the terms "cast metal product," "cast product," "cast aluminum alloy product," and the like are used interchangeably and refer to products produced by direct chill casting (including direct chill co-casting) or semi-continuous casting, continuous casting (including, for example, by use of a twin belt caster, twin roll caster, block caster, or any other continuous casting machine), electromagnetic casting, hot top casting, or any other casting process.

[0035] As used herein, the meaning of "room temperature" can include a temperature of about 15° C. to about 30° C., such as about 15° C., about 16° C., about 17° C., about 18° C., about 19° C., about 20° C., about 21° C., about 22° C., about 23° C., about 24° C., about 25° C., about 26° C., about 27° C., about 28° C., about 29° C., or about 30° C. As used herein, the meaning of "ambient conditions" can include a temperature of about room temperature, a relative humidity of about 20% to about 100%, and an atmospheric pressure of about 975 millibars (mbar) to about 1050 mbar. For example, the relative humidity may be about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%, about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about 39%, about 40%, about 41%, about 42%, about 43%, about 44%, about 45%, about 46%, about 47%, about 48%, about 49%, about 50%, about 51%, about 52%, about 53%, about 54%, about 55%, about 56%, about 57%, about 58%, about 59%, about 60%, about 61%, about 62%, about 63%, about 64%, about 65%, about 66%, about 67%, about 68%, about 69%, about 70%, about 71%, about 72%, about 73%, about 74%, about 75%, about 76%, about 77%, about 78%, about 79%, about 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, about 100%, about 101%, about 102%, about 103%, about 104%, about 105%, about 106%, about 107%, about 108%, about 109%, about 110%, about 111%, about 112%, about 113%, about 114%, about 115%, about 116%, about %, about 62%, about 63%, about 64%, about 65%, about 66%, about 67%, about 68%, about 69%, about 70%, about 71%, about 72%, about 73%, about 74%, about 75%, about 76%, about 77%, about 78%, about 79%, about 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, about 100%, or anywhere therebetween. For example, the air pressure can be about 975 mbar, about 980 mbar, about 985 mbar, about 990 mbar, about 995 mbar, about 1000 mbar, about 1005 mbar, about 1010 mbar, about 1015 mbar, about 1020 mbar, about 1025 mbar, about 1030 mbar, about 1035 mbar, about 1040 mbar, about 1045 mbar, about 1050 mbar, or anywhere therebetween.

[0036] All ranges disclosed herein should be understood to encompass all subranges subsumed therein. For example, the stated range "1-10" should be considered to encompass all subranges between a minimum value of 1 and a maximum value of 10, inclusive. That is, all subranges begin with a minimum value of 1 or greater (e.g., 1-6.1) and end with a maximum value of 10 or less (e.g., 5.5-10). Unless otherwise stated, the expression "maximum," when referring to a compositional amount of an element, means that the element is optional and includes a zero percent composition of that particular element. Unless otherwise stated, all compositional percentages are weight percent (wt.%).

[0037] As used herein, the meanings of "a," "an," and "the" include singular and plural references unless the context clearly indicates otherwise.

[0038] As an example, aluminum alloy products and their components may be listed in terms of their elemental composition in weight percent (wt.%), with the maximum wt.% being 0.15% for the sum of all impurities in each alloy, with the remainder being aluminum.

[0039] Accompanying elements (e.g., grain refiners and deoxidizers), or other additives, may be present in the present invention and may themselves add other properties without deviating from or significantly altering the properties of the alloys described herein or the alloys described herein.

[0040] Inevitably impurities (including materials or elements) may be present in small amounts in the alloy due to the inherent properties of aluminum or due to dissolution from contact with processing equipment. As noted, some alloys may contain up to about 0.25 wt.% of any element in addition to the alloying elements, incidental elements, and inevitable impurities.

[0041] Methods for producing alloys and aluminum alloy products The aluminum alloy products described herein (e.g., aluminum alloy sheet metal substrates) may be prepared using any suitable method, for example, the aluminum alloy may be cast, homogenized, hot rolled, cold rolled, heat treated, formed, etc. to produce the aluminum alloy product.

[0042] FIG. 2 outlines an example method for making an aluminum alloy product. The method of FIG. 2 begins at 205, where an aluminum alloy 206 is cast to form a cast aluminum alloy product 207 (e.g., an ingot or other cast product). At 210, the cast aluminum alloy product 207 is homogenized to form a homogenized aluminum alloy product 211. At 215, the homogenized aluminum alloy product 211 is subjected to one or more hot rolling passes and / or one or more cold rolling passes to form a rolled aluminum alloy product 212, which may correspond to an aluminum alloy article (e.g., an aluminum alloy plate, an aluminum alloy shade, or an aluminum alloy sheet). Optionally, the rolled aluminum alloy product 212 is subjected to further processing steps, as described below, to form an aluminum alloy article.

[0043] Non-limiting examples of casting processes include a direct chill (DC) casting process or a continuous casting (CC) process. For example, in FIG. 2, a schematic diagram of a DC casting process is shown at 205, although other casting processes can be used. A continuous casting system can include a pair of moving opposed casting surfaces (e.g., moving opposed belts, rolls, or blocks), a casting cavity between the pair of moving opposed casting surfaces, and a molten metal injector. The molten metal injector can have an end opening through which molten metal can exit the molten metal injector and be injected into the casting cavity.

[0044] The cast aluminum alloy product (e.g., cast ingot, cast slab, or other cast product) may be processed by any desired technique. Optionally, the processing step may be used to prepare a rolled aluminum alloy product (e.g., aluminum alloy sheet). Examples of optional processing steps include, without limitation, homogenization, hot rolling, cold rolling, annealing, solution heat treatment, and pre-aging.

[0045] In the homogenization step, the cast product may be heated to a temperature ranging from about 400° C. to about 600° C. For example, the cast product may be heated to a temperature of about 400° C., about 410° C., about 420° C., about 430° C., about 440° C., about 450° C., about 460° C., about 470° C., about 480° C., about 490° C., about 500° C., about 510° C., about 520° C., about 530° C., about 540° C., about 550° C., about 560° C., about 570° C., about 580° C., about 590° C., or about 600° C. The product may then be soaked (i.e., held at the indicated temperature) for a period of time to form a homogenized product. In some examples, the total time for the homogenization step (including the heating and soaking stages) may be up to 24 hours. For example, the homogenization step may involve heating and soaking the product to up to 500°C-600°C for a total time of up to 18 hours. Optionally, the homogenization step may involve heating and soaking the product to less than 490°C for a total time of more than 18 hours. In some cases, the homogenization step may include multiple processes. In some non-limiting examples, the homogenization step may involve heating the cast product to a first temperature for a first time, followed by heating to a second temperature for a second time. For example, the cast product may be heated to about 465°C for about 3.5 hours, and then heated to about 480°C for about 6 hours.

[0046] Following the homogenization step, a hot rolling step can optionally be performed. Before starting the hot rolling, the homogenized product can be cooled to a temperature between 300° C. and 450° C. For example, the homogenized product can be cooled to a temperature between 325° C. and 425° C. or between 350° C. and 400° C. The homogenized product is then hot rolled at a temperature of 300°C to 450°C to form a hot rolled plate, hot rolled shade, or hot rolled sheet having a gauge of 3mm to 200mm (e.g., 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, or anywhere therebetween).

[0047] Optionally, the cast product may be a continuous cast product that may be cooled to a temperature of 300° C. to 450° C. For example, the continuous cast product may be cooled to a temperature of 325° C. to 425° C. or 350° C. to 400° C. The continuous cast product is then hot rolled at a temperature of 300°C to 450°C to form a hot rolled plate, hot rolled shade, or hot rolled sheet having a gauge of 3mm to 200mm (e.g., 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, or anywhere therebetween). During hot rolling, the temperature and other operating parameters can be controlled so that the temperature of the hot rolled intermediate product leaving the hot rolling mill is 470°C or less, 450°C or less, 440°C or less, or 430°C or less.

[0048] The cast, homogenized, or hot rolled product can optionally be cold rolled using a cold rolling mill to produce a thinner product (e.g., cold rolled sheet). The cold rolled product can have a gauge of about 0.5-10 mm, for example, about 0.7-6.5 mm. Optionally, the cold rolled product can have a gauge of 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm, 7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm, 9.0 mm, 9.5 mm, or 10.0 mm. Cold rolling can be performed to a final gauge thickness that represents up to an 85% gauge reduction (e.g., up to 10%, up to 20%, up to 30%, up to 40%, up to 50%, up to 60%, up to 70%, up to 80%, or up to 85% reduction) compared to the gauge before cold rolling began. Optionally, an intermediate annealing step can be performed during the cold rolling steps. For example, a first cold rolling process is applied, followed by an annealing process (intermediate annealing), followed by a second cold rolling process. The intermediate annealing step can be performed at a temperature between about 300°C and about 450°C (e.g., about 310°C, about 320°C, about 330°C, about 340°C, about 350°C, about 360°C, about 370°C, about 380°C, about 390°C, about 400°C, about 410°C, about 420°C, about 430°C, about 440°C, or about 450°C). In some cases, the intermediate annealing step includes multiple processes. In some non-limiting examples, the intermediate annealing step includes heating the partially cold rolled product to a first temperature for a first time, followed by heating to a second temperature for a second time. For example, the partially cold rolled product can be heated to about 410°C for about 1 hour, and then heated to about 330°C for about 2 hours.

[0049] The cast, homogenized, or rolled product may then optionally undergo a solution heat treatment step. The solution heat treatment step may be any suitable treatment of the product that results in solution of the soluble particles. The cast, homogenized, or rolled product may be heated to a peak metal temperature (PMT) of up to 590°C (e.g., 400°C-590°C) and soaked at the PMT for a period of time to form a hot product. For example, the cast, homogenized, or rolled product may be soaked at 480°C for a soak time of up to 30 minutes (e.g., 0 seconds, 60 seconds, 75 seconds, 90 seconds, 5 minutes, 10 minutes, 20 minutes, 25 minutes, or 30 minutes). After heating and soaking, the hot product is quenched at a rate of more than 200°C / s to a temperature of 500-200°C to form a heat treated product. In one example, the hot product is cooled to a temperature between 450°C and 200°C at a quench rate of greater than 200°C / sec. Optionally, in other cases, the cooling rate can be faster. Optionally, in other cases, the temperature can be lower. In one example, the hot product is cooled to a temperature between 450°C and 200°C at a quench rate of greater than 200°C / sec.

[0050] After quenching, the heat treated product can optionally be pre-aged by reheating before winding. Pre-aging can be performed at a temperature of about 70°C to about 125°C for a period of time up to 6 hours. For example, pre-aging can be performed at a temperature of about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, about 95°C, about 100°C, about 105°C, about 110°C, about 115°C, about 120°C, or about 125°C. Optionally, pre-aging can be performed for about 30 minutes, about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, or about 6 hours. Pre-aging can be performed by passing the heat treated product through a heating device, such as a device that emits radiant heat, convective heat, induction heat, infrared heat, or the like.

[0051] The cast products described herein can be used to make products in the form of sheets, plates, or other suitable products. For example, plates comprising the products described herein can be prepared by processing an ingot in a homogenization step or by casting the product in a continuous caster followed by a hot rolling step. In the hot rolling step, the cast products can be hot rolled to a thickness gauge of 200 mm or less (e.g., about 10 mm to about 200 mm). For example, the cast products can be hot rolled into plates with a final gauge thickness of about 10 mm to about 175 mm, about 15 mm to about 150 mm, about 20 mm to about 125 mm, about 25 mm to about 100 mm, about 30 mm to about 75 mm, or about 35 mm to about 50 mm. In some cases, the plates may be rolled into thinner metal products (e.g., sheets).

[0052] Methods of using the disclosed aluminum alloy products The aluminum alloy products described herein (e.g., electrically insulated aluminum alloy products) can be used in automotive applications and other transportation applications, including aircraft and rail applications. For example, the disclosed aluminum alloy products can be used to prepare automotive structural components, such as bumpers, side beams, roof beams, cross beams, pillar reinforcements (e.g., A-pillars, B-pillars, and C-pillars), inner panels, outer panels, side panels, inner hoods, outer hoods, or trunk lid panels. The aluminum alloy products and methods described herein can also be used in aircraft or rail vehicle applications, for example, to prepare exterior and interior panels.

[0053] The aluminum alloy products described herein (e.g., electrically insulated aluminum alloy products and disclosed methods) can also be used in electronics applications. For example, the aluminum alloy products and methods described herein can be used to prepare housings for electronic devices, including mobile phones and tablet computers. In some examples, the aluminum alloy products can be used to prepare housings for mobile phones (e.g., smartphones), tablet bottom chassis, and external casings for other electronics.

[0054] Methods for processing and using metal alloys Described herein are methods for processing metals and metal alloys, including aluminum, aluminum alloys, magnesium, magnesium alloys, magnesium composites, and steel, among others, and the resulting processed metals and metal alloys. In some examples, the metals used in the methods described herein include aluminum alloys, such as 1xxx series aluminum alloys, 2xxx series aluminum alloys, 3xxx series aluminum alloys, 4xxx series aluminum alloys, 5xxx series aluminum alloys, 6xxx series aluminum alloys, 7xxx series aluminum alloys, or 8xxx series aluminum alloys. In some examples, the materials used in the methods described herein include non-ferrous materials, such as aluminum, aluminum alloys, magnesium, magnesium-based materials, magnesium alloys, magnesium composites, titanium, titanium-based materials, titanium alloys, copper, copper-based materials, composites, sheets used in composites, or any other suitable metals, non-metals, or combinations of materials. Monolithic, as well as non-monolithic, such as roll-bonded materials, clad alloys, clad layers, composite materials (such as, without limitation, carbon fiber-containing materials), or a variety of other materials are also useful in the methods described herein. In some examples, aluminum alloys containing iron are useful in the methods described herein.

[0055] As non-limiting examples, typical 1××× series aluminum alloys for use in the methods described herein can include AA1100, AA1100A, AA1200, AA1200A, AA1300, AA1110, AA1120, AA1230, AA1230A, AA1235, AA1435, AA1145, AA1345, AA1445, AA1150, AA1350, AA1350A, AA1450, AA1370, AA1275, AA1185, AA1285, AA1385, AA1188, AA1190, AA1290, AA1193, AA1198, or AA1199.

[0056] Non-limiting exemplary 2××× series aluminum alloys for use in the methods described herein include AA2001, A2002, AA2004, AA2005, AA2006, AA2007, AA2007A, AA2007B, AA2008, AA2009, AA2010, AA2011, AA2011A, AA2111, AA2111A, AA2111B, AA2012, AA2013, AA 2014, AA2014A, AA2214, AA2015, AA2016, AA2017, AA2017A, AA2117, AA2018, AA2218, AA2618, AA2618A, AA22 19, AA2319, AA2419, AA2519, AA2021, AA2022, AA2023, AA2024, AA2024A, AA2124, AA2224, AA2224A, AA2324, A A2424, AA2524, AA2624, AA2724, AA2824, AA2025, AA2026, AA2027, AA2028, AA2028A, AA2028B, AA2028C, AA2 029, AA2030, AA2031, AA2032, AA2034, AA2036, AA2037, AA2038, AA2039, AA2139, AA2040, AA2041, AA2044, AA AA2045, AA2050, AA2055, AA2056, AA2060, AA2065, AA2070, AA2076, AA2090, AA2091, AA2094, AA2095, AA2195, AA2295, AA2196, AA2296, AA2097, AA2197, AA2297, AA2397, AA2098, AA2198, AA2099, or AA2199.

[0057] Non-limiting exemplary 3××× series aluminum alloys for use in the methods described herein include AA3002, AA3102, AA3003, AA3103, AA3103A, AA3103B, AA3203, AA3403, AA3004, AA3004A, AA3104, AA3204, AA3304, AA3005, AA3005A, AA3105, AA3105A, AA3105B, AA AA3007, AA3107, AA3207, AA3207A, AA3307, AA3009, AA3010, AA3110, AA3011, AA3012, AA3012A, AA3013, AA3014, AA3015, AA3016, AA3017, AA3019, AA3020, AA3021, AA3025, AA3026, AA3030, AA3130, or AA3065.

[0058] Non-limiting exemplary 4xxx series aluminum alloys for use in the methods described herein can include AA4004, AA4104, AA4006, AA4007, AA4008, AA4009, AA4010, AA4013, AA4014, AA4015, AA4015A, AA4115, AA4016, AA4017, AA4018, AA4019, AA4020, AA4021, AA4026, AA4032, AA4043, AA4043A, AA4143, AA4343, AA4643, AA4943, AA4044, AA4045, AA4145, AA4145A, AA4046, AA4047, AA4047A, or AA4147.

[0059] Non-limiting exemplary 5xxx series aluminum alloys for use in the methods of manufacture described herein include AA5182, AA5183, AA5005, AA5005A, AA5205, AA5305, AA5505, AA5605, AA5006, AA5106, AA5010, AA5110, AA5110A, AA5210, AA5310, AA5016, AA5017, AA5018, AA5018A, AA5019, AA5019A , AA5119, AA5119A, AA5021, AA5022, AA5023, AA5024, AA5026, AA5027, AA5028, AA5040, AA5140, AA5041, AA5042, AA5043, AA5049, AA5149, AA5249, AA5349, AA5449, AA5449A, AA5050, AA5050A, AA5050C, AA5150, AA5051, AA5051A, AA5151, AA525 1, AA5251A, AA5351, AA5451, AA5052, AA5252, AA5352, AA5154, AA5154A, AA5154B, AA5154C, AA5254, AA5354, AA5454, AA5 554, AA5654, AA5654A, AA5754, AA5854, AA5954, AA5056, AA5356, AA5356A, AA5456, AA5456A, AA5456B, AA5556, AA5556A, AA5556B, AA5556C, AA5257, AA5457, AA5557, AA5657, AA5058, AA5059, AA5070, AA5180, AA5180A, AA5082, AA5182, AA5083, AA5183, AA5183A, AA5283, AA5283A, AA5283B, AA5383, AA5483, AA5086, AA5186, AA5087, AA5187, or AA5088.

[0060] Non-limiting exemplary 6××× series aluminum alloys for use in the methods described herein include AA6101, AA6101A, AA6101B, AA6201, AA6201A, AA6401, AA6501, AA6002, AA6003, AA6103, AA6005, AA6005A, AA6005B, AA6005C, AA6105, AA6205, AA6305, AA6006, AA6106, AA6206, AA 6306, AA6008, AA6009, AA6010, AA6110, AA6110A, AA6011, AA6111, AA6012, AA6012A, AA6013, AA6113, AA6014, AA6015 , AA6016, AA6016A, AA6116, AA6018, AA6019, AA6020, AA6021, AA6022, AA6023, AA6024, AA6025, AA6026, AA6027, AA60 28, AA6031, AA6032, AA6033, AA6040, AA6041, AA6042, AA6043, AA6151, AA6351, AA6351A, AA6451, AA6951, AA6053, AA 6055, AA6056, AA6156, AA6060, AA6160, AA6260, AA6360, AA6460, AA6460B, AA6560, AA6660, AA6061, AA6061A, AA6261 , AA6361, AA6162, AA6262, AA6262A, AA6063, AA6063A, AA6463, AA6463A, AA6763, A6963, AA6064, AA6064A, AA6065, AA6066, AA6068, AA6069, AA6070, AA6081, AA6181, AA6181A, AA6082, AA6082A, AA6182, AA6091, or AA6092.

[0061] Non-limiting exemplary 7xxx series aluminum alloys for use in the methods described herein include AA7011, AA7019, AA7020, AA7021, AA7039, AA7072, AA7075, AA7085, AA7108, AA7108A, AA7015, AA7017, AA7018, AA7019A, AA7024, AA7025, AA7028, AA7030, AA7031, AA7033, AA7035, AA7035A, AA7046, AA7046A, AA7003, AA7004, AA7005, A A7009, AA7010, AA7011, AA7012, AA7014, AA7016, AA7116, AA7122, AA7023, AA7026, AA7029, AA71 29, AA7229, AA7032, AA7033, AA7034, AA7036, AA7136, AA7037, AA7040, AA7140, AA7041, AA7049, AA7049A, AA7149, AA7204, AA7249, AA7349, AA7449, AA7050, AA7050A, AA7150, AA7250, AA7055, A Examples include A7155, AA7255, AA7056, AA7060, AA7064, AA7065, AA7068, AA7168, AA7175, AA7475, AA7076, AA7178, AA7278, AA7278A, AA7081, AA7181, AA7185, AA7090, AA7093, AA7095, or AA7099.

[0062] Non-limiting exemplary 8××× series aluminum alloys for use in the methods described herein include AA8005, AA8006, AA8007, AA8008, AA8010, AA8011, AA8011A, AA8111, AA8211, AA8112, AA8014, AA8015, AA8016, AA8017, AA8018, AA8019, AA802 1, AA8021A, AA8021B, AA8022, AA8023, AA8024, AA8025, AA8026, AA8030, AA8130, AA8040, AA8050, AA8150, AA8076, AA8076A, AA8176, AA8077, AA8177, AA8079, AA8090, AA8091, or AA8093.

[0063] 3 shows a schematic overview of a method for processing a sheet metal substrate 305 (including, for example, an aluminum alloy sheet metal substrate) to produce an electrically insulated metal product. The sheet metal substrate 305 is optionally fed into a pretreatment coating application system 310, where a pretreatment coating is applied to the sheet metal substrate 305. The pretreatment coating application system 310 can be any suitable system for applying a pretreatment coating to the sheet metal substrate 305. A first enlarged inset in FIG. 3 shows a pretreatment layer 306 applied to the sheet metal substrate 305.

[0064] In some cases, the sheet metal substrate 305 may be treated prior to entering the pretreatment coating application system. In some embodiments, the surface of the sheet metal substrate 305 may be degreased (e.g., using an acidic or alkaline solution) to clean the surface. In some embodiments, the sheet metal substrate 305 may be preheated prior to entering the pretreatment coating application system.

[0065] Optionally, the sheet metal substrate 305 can be processed in an adhesive application system 315 to apply an adhesive to a surface of the sheet metal substrate 305. Such a system is useful when a polymer layer is to be bonded to the sheet metal substrate using an adhesive. It is understood that the use of an adhesive to bond the polymer film to the sheet metal substrate 305 is optional. If no adhesive is used to bond the polymer film to the sheet metal substrate 305, the adhesive application system 315 can be omitted. Optionally, the adhesive application system 315 includes a roll coating system for applying an acrylic adhesive, a polyester adhesive, an epoxy adhesive, or the like.

[0066] The sheet metal substrate 305 is optionally advanced to a preheat oven 320 to heat the sheet metal substrate 305 to a preheat temperature (T1). If the polymer film 325 to be applied includes a sealing layer, the preheat temperature T1 may be higher than the melting temperature of the sealing layer. In some embodiments, the preheating temperature T1 is 175°C to 300°C, for example, 175°C to 290°C, 175°C to 280°C, 175°C to 270°C, 175°C to 260°C, 175°C to 250°C, 185°C to 300°C, 185°C to 290°C, 185°C to 280°C, 185°C to 270°C, 185°C to 260°C, 185°C to 250°C, 195°C to 300°C, 195°C to 290°C, 195°C to 280°C, 195°C to 270°C, 195°C to 260°C, 1 95°C to 250°C, 205°C to 300°C, 205°C to 290°C, 205°C to 280°C, 205°C to 270°C, 205°C to 260°C, 205°C to 250°C, 215°C to 300°C, 215°C to 290°C, 215°C to 280°C, 215°C to 270°C, 215°C to 260°C, 215°C to 250°C, 225°C to 300°C, 225°C to 290°C, 225°C to 280°C, 225°C to 270°C, 225°C to 260°C, or 225°C to 250°C. As for the lower limit, T1 may be greater than 175°C, for example greater than 185°C, greater than 195°C, greater than 205°C, or greater than 215°C. With respect to the upper limit, T1 may be less than 300°C, e.g., less than 290°C, less than 280°C, less than 270°C, less than 260°C, or less than 250°C. Optionally, the sheet metal substrate 305 may proceed through the pretreatment coating application system 310, adhesive application system 315, and preheat oven 320 in any order. Optionally, one or more of the pretreatment coating application system 310, adhesive application system 315, or preheat oven 320 are not used. Pretreatment coating examples include, without limitation, Ti-Zr based conversion coatings, Cr based conversion coatings, or copolymer based coatings, e.g., poly(vinylphosphonic acid-co-acrylic acid) coating layers. Although the preheat oven 320 is described as an oven, any suitable heating method may be used, e.g., induction systems, application of infrared heat, contact with a heated roll, gas-fired ovens, electrically heated ovens, and the like.

[0067] After pre-treatment, adhesive application, and / or pre-heating (if used), the sheet metal substrate 305 passes through a lamination system 330 to apply a polymer film 325 to one side of the sheet metal substrate 305. In some cases, the polymer film 325 can be applied to both sides of the sheet metal substrate 305. The lamination system 330 can be any suitable system for laminating the polymer film 325 to the sheet metal substrate 305. In some cases, the lamination system 330 is a hot melt lamination system. The laminated sheet metal substrate exits the lamination system 330, combining the sheet metal substrate 305 with the multi-layer polymer insulation structure 326 bonded thereto.

[0068] Figure 4 illustrates a schematic diagram of a stacking system 400 according to certain embodiments of the present disclosure. The stacking system 400 may be the stacking system 330 of Figure 3 or may be another stacking system. Certain elements illustrated in Figure 4 are shown at an exaggerated scale for illustrative purposes only.

[0069] The lamination system 400 can include a pair of rollers 405 between which the sheet metal substrate 410 can pass. The sheet metal substrate 410 can include a sheet metal base layer 415. The sheet metal base layer 415 has been pretreated, for example, by the pretreatment coating application system 310 of FIG. 3, and optionally has an adhesive layer thereon, for example, applied by the adhesive application system 315 of FIG. 3, and / or is preheated, for example, by the preheat oven 320 of FIG. 3. In some cases, the pretreated sheet metal substrate 410 includes one or more pretreatment layers 420 (e.g., one or more conversion coatings, oxide layers, anodization layers, polymer pretreatments, etc.). In some examples, the pretreatment layer 420 includes a Ti-Zr based conversion coating, a Cr based conversion coating, or a copolymer based coating, for example, a poly(vinylphosphonic acid-co-acrylic acid) coating layer.

[0070] As it passes through the rollers 405, the polymer film 425 can be pressed against the sheet metal substrate 410 to produce a laminated sheet metal substrate 430. In some cases, the single lamination system 400 can include an additional set of rollers to apply a second polymer film to an opposite side of the sheet metal substrate 410 from the polymer film 425. In some cases, the single pair of rollers 405 can further apply a second polymer film to an opposite side of the sheet metal substrate 410 from the polymer film 425. Although not shown in FIG. 4, the polymer film 425 can optionally include a multi-layer structure (e.g., a sealing polymer layer and a top polymer layer, or an adhesive layer and a top polymer layer) or the sheet metal substrate can optionally include an adhesive layer thereon, for example, on the pretreatment layer 420 (if present).

[0071] Returning to FIG. 3, after lamination, the sheet metal substrate 305 having the multi-layer polymeric insulating structure 326 thereon may proceed into an annealing oven 335, which may be optional. In some cases, the annealing oven 335 is located immediately downstream of the lamination system 330 such that the sheet metal substrate 305 having the multi-layer polymeric insulating structure 326 thereon proceeds into the annealing oven 335 after exiting the lamination system 330 before proceeding into or contacting other machinery or systems. The annealing oven 335 increases the temperature of the sheet metal substrate 305 having the multi-layer polymeric insulating structure 326 thereon to an annealing temperature (T A The annealing temperature T A is optionally the melting temperature (T m Optionally, the annealing temperature T A is the melting temperature (T m In some embodiments, the annealing temperature T Ais 175°C to 275°C, for example, 175°C to 180°C, 180°C to 185°C, 185°C to 190°C, 190°C to 195°C, 195°C to 200°C, 200°C to 205°C, 205°C to 210°C, 210°C to 215°C, 215°C to 220°C, 220°C to 225°C, 225°C to 230°C, 230°C to 235°C, 235°C to 240°C, 240°C to 245°C, 245°C to 250°C, 250°C to 255°C, 255°C to 260°C, 260°C to 265°C, 265°C to 270°C, or 270°C to 275°C. A may be greater than 175° C., for example, greater than 175° C., greater than 180° C., greater than 185° C., greater than 190° C., greater than 195° C., or greater than 200° C. A may be less than 275°C, e.g., less than 275°C, less than 270°C, less than 265°C, less than 260°C, less than 255°C, less than 250°C, less than 245°C, less than 240°C, less than 235°C, less than 230°C, or less than 225°C.

[0072] The sheet metal substrate 305 having the multi-layered polymer insulating structure 326 thereon is spent in the annealing oven 335 for a sufficient length of time to impart the desired properties to the sheet metal substrate 305 having the multi-layered polymer insulating structure 326 thereon, including annealing the sheet metal substrate 305 and achieving the desired adhesion of the polymer film 325. The time in the annealing oven 335 can be based, for example, on the oven length and the speed of the sheet metal substrate. In some cases, the time can be within a range of about 2 seconds to about 30 seconds, about 9 seconds to about 15 seconds, about 10 seconds to about 14 seconds, or about 12 seconds. In some cases, the time can be adjusted (e.g., by adjusting the speed of the sheet metal substrate) as needed to compensate for changes in temperature in the annealing oven 335. The enlarged inset of the laminated and annealed sheet metal substrate 340 in FIG. 3 shows the sheet metal substrate 305, the pretreatment layer 306, and the multi-layered polymer insulating structure 326 (including the bonding layer 321 and the top polymer layer 322). In some examples, the bonding layer 321 may be, for example, an adhesive layer applied in the adhesive application system 315 or present on the polymer film 325. In some examples, the bonding layer 321 may be a polymer sealing layer or a low melting point polymer layer of the polymer film 325.

[0073] After exiting the annealing oven 335, the laminated annealed sheet metal substrate 340 may optionally be quenched, for example in air or a volume of a quenching liquid (e.g., water), or by application of a coolant to the laminated annealed sheet metal substrate 340. The laminated annealed sheet metal substrate 340 may be quenched or otherwise cooled immediately after exiting the annealing oven 335. In some cases, or for some applications, the laminated annealed sheet metal substrate 340 may be optionally subjected to a lacquer process to apply an optional lacquer layer to a second side of the laminated annealed sheet metal substrate 340.

[0074] After exiting the annealing oven, the laminated and annealed sheet metal substrate 340 can be subjected to further processing. In some examples, the laminated and annealed sheet metal substrate 340 can be rolled up as is, for example, for shipping or further processing. Optionally, the laminated and annealed sheet metal substrate 340 can be processed in a punching or cutting system 345 to prepare electrically insulated sheet metal blanks or electrically insulated sheet metal strips or segments. The punching or cutting system 345 can include any suitable system for cutting or punching the laminated and annealed sheet metal substrate 340 in some examples to create smaller electrically insulated sheet metal products, which can be subjected to further processing. Although the punching or cutting system 345 is shown downstream of the annealing oven 335, in some examples the punching or cutting system 345 may be upstream of the annealing oven 335 and the punched or cut laminated sheet metal product may be subjected to annealing in the annealing oven 335.

[0075] Optionally, the laminated and annealed sheet metal substrate 340, or smaller electrically insulated sheet metal products cut or punched from the laminated and annealed sheet metal substrate 340, may be subjected to shaping, for example, by any suitable forming system (including, for example, roll forming equipment, stamping equipment, punching equipment, etc.). In some examples, multiple different types of forming equipment may be used, for example, to prepare electrically insulated sheet metal products of different shapes. Punching / cutting and forming (if used) may be performed in any desired order, for example, forming first and punching or cutting second, or punching or cutting first and forming second. In some cases, one or both of punching / cutting and forming are not used.

[0076] In some examples, the electrically isolated sheet metal fabrications can be assembled into or as part of a structural enclosure for a device. FIG. 5 illustrates an example structural enclosure 500 for a device 505 in an exploded view. The structural enclosure 500 is shown as including multiple electrically isolated sheet metal fabrications 510 (e.g., bottom, top, front, back, and two sides) that surround the device 505. The electrically isolated sheet metal fabrications 510 can include any of the electrically isolated sheet metal fabrications described herein and can include a sheet metal base layer and a multi-layer polymeric insulating structure on an inner surface that faces the device 505.

[0077] The examples disclosed herein serve to further illustrate aspects of the present invention, but at the same time do not constitute any limitation thereof. On the contrary, it should be clearly understood that recourse may be had to various embodiments, modifications thereof, and equivalents, which may suggest themselves to those skilled in the art after reading the description herein, without departing from the spirit of the present invention. The examples and embodiments described herein may also utilize conventional procedures, unless otherwise indicated. Some procedures are described herein for illustrative purposes.

[0078] Example 1 To evaluate electrical insulation performance and adhesion properties, various electrically insulated metal product samples were prepared by applying a polyethylene terephthalate (PET) film onto an aluminum alloy sheet metal base. Table 1 shows an overview of the various samples prepared. [Table 1]

[0079] A sample (Sample 1) included a polymer film with an adhesive layer pre-attached thereto and was applied directly onto an aluminum alloy sheet metal base using application of pressure only or application of pressure and heat. Three samples (Samples 2-4) were prepared by applying a thin adhesive layer onto an aluminum alloy sheet metal base and then laminating a polymer film onto the adhesive layer using pressure and heat. Three samples (Samples 5-7) were prepared by laminating a polymer film directly onto an aluminum alloy sheet metal base using pressure and heat followed by an annealing process in Samples 5-7.

[0080] The samples were subjected to standard tests for electrical resistivity (surface and volume resistivity, average of 10 samples), dielectric strength (breakdown resistance, average of 10 samples), and comparative tracking index (CTI) measurements (no breakage after 50 drops on 5 samples). Table 2 summarizes the results obtained. [Table 2]

[0081] Where results were available, surface and volume resistivity measurements showed very high resistance for all samples, indicating that good electrical insulation was achieved by the polymer film. Similarly, dielectric strength measurements showed very high breakdown voltages, well above 5 kV, again indicating that good electrical insulation was achieved by the polymer film. CTI values ​​for all films were measured at approximately 200-250 V. Figure 6 shows optical images of samples 1, 2, 5, and 6 after CTI testing, indicating similar performance by all films. The black bars in the images in Figure 6 represent approximately 1 mm. Samples laminated on 200 μm aluminum substrates were also subjected to vertical flammability testing (UL94), and all samples received a V-0 flammability test rating.

[0082] The samples were subjected to cross-cut testing to evaluate the adhesion performance of the polymer film on the aluminum alloy sheet metal substrate. The adhesion performance can be important in limiting the delamination of the polymer film during post-annealing and cooling treatment. A series of cross-cuts were applied at right angles to each other and spaced approximately 1 mm apart, followed by an adhesion tape test to apply a peel force to the polymer film to test for delamination of the film from the aluminum substrate. Figure 7 shows optical images of some samples after cross-cut testing. Significant delamination of the film from the substrate was observed for sample 1, indicating poor adhesion. Less delamination of the film from the substrate was observed for samples 2 and 3, indicating better adhesion. Little delamination of the film from the substrate was observed for samples 6 and 7, indicating good adhesion. Exemplary Aspects

[0083] As used hereinafter, any reference to a series of embodiments (e.g., "Embodiments 1-4") or an unrecited group of embodiments (e.g., "any preceding or subsequent embodiment") should be understood as a disjunctive reference to each of those embodiments (e.g., "Embodiments 1-4" should be understood as "Embodiments 1, 2, 3, or 4").

[0084] Aspect 1 is an electrically insulated metal article comprising an aluminum alloy sheet metal substrate and a multilayer polymeric insulating structure bonded to the aluminum alloy sheet metal substrate, the multilayer polymeric insulating structure comprising a bonding layer adjacent to the aluminum alloy sheet metal substrate and a top polymer layer on the bonding layer, the multilayer polymeric insulating structure having a thickness of 5 μm to 100 μm, and the multilayer polymeric insulating structure bonded to the aluminum alloy sheet metal substrate as a whole has a surface resistivity of 1×10 12 Ω~1×10 15 Ω, volume resistivity is 1×10 12 Ω~1×10 15Ω, a breakdown voltage of 2 kV to 50 kV, or a comparative tracking index value of 175 V to 400 V.

[0085] Example 2 is the electrically insulated metal product of any of the preceding or subsequent examples, wherein the bonding layer comprises a first polyester film and the top polymer layer comprises a second polyester film having a different composition than the first polyester film.

[0086] Example 3 is an electrically insulated metal product of any preceding or subsequent example, wherein the bonding layer includes a polymer sealing layer exhibiting a first melting temperature, and the top polymer layer exhibits a second melting temperature or decomposition temperature higher than the first melting temperature.

[0087] Example 4 is the electrically insulated metal product of any of the preceding or subsequent examples, wherein the first melting temperature is between 150°C and 250°C or the polymer sealing layer is bonded to the aluminum alloy sheet metal substrate after preheating to between 150°C and 250°C.

[0088] Example 5 is the electrically insulated metal article of any preceding or subsequent example, wherein the top polymer layer comprises polyethylene, polypropylene, and / or polyethylene terephthalate.

[0089] Example 6 is the electrically insulated metal product of any of the preceding or subsequent examples, wherein the multilayer polymeric insulation structure is a laminated multilayer film applied to the aluminum alloy sheet metal substrate under lamination conditions including exposure to a lamination temperature of 175°C to 300°C and / or exposure to a lamination pressure of 1 bar to 7 bar.

[0090] Example 7 is the electrically insulated metal article of any of the preceding or subsequent examples, wherein the multilayer polymeric insulating structure is an annealed multilayer film that has been subjected to annealing conditions of 175°C to 300°C.

[0091] Example 8 is the electrically isolated metal product of any preceding or subsequent example, wherein no adhesive layer is disposed between the aluminum alloy sheet metal substrate and the multilayer polymeric insulation structure.

[0092] Example 9 is the electrically isolated metal product of any preceding or subsequent example, wherein the bonding layer comprises an adhesion layer between the aluminum alloy sheet metal substrate and the top polymer layer.

[0093] Example 10 is the electrically insulated metal product of any of the preceding or subsequent examples, wherein the adhesion layer is disposed on the aluminum alloy sheet metal substrate prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer; or the adhesion layer is disposed on the top polymer layer prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer.

[0094] Example 11 is the electrically isolated metal product of any preceding or subsequent example, wherein the multilayer polymeric insulation structure is free of pinholes or other defects that provide a conductive path to the aluminum alloy sheet metal substrate.

[0095] Example 12 is the electrically isolated metal product of any preceding or subsequent example, wherein the aluminum alloy sheet metal substrate includes a surface pretreatment coating on an aluminum alloy sheet metal base layer.

[0096] Example 13 is the electrically isolated metal product of any preceding or subsequent example, wherein the surface pretreatment coating comprises a Ti—Zr based conversion coating, a Cr based conversion coating, or a copolymer based coating.

[0097] Example 14 is the electrically insulated metal product of any of the preceding or subsequent examples, wherein the aluminum alloy sheet metal substrate has a non-planar shape or is in a formed configuration.

[0098] A fifteenth aspect is a method for preparing an electrically insulated metal product, the method comprising preheating an aluminum alloy sheet metal substrate to a first temperature of 150° C. to 250° C. and bonding a multilayer polymeric insulating structure to a surface of the aluminum alloy sheet metal substrate to produce a bonded product, the multilayer polymeric insulating structure including a bonding layer and a top polymer layer on the bonding layer, the multilayer polymeric insulating structure having a thickness of 5 μm to 100 μm, and the multilayer polymeric insulating structure bonded to the aluminum alloy sheet metal substrate has an overall surface resistance of 1×10 12 Ω~1×10 15 Ω, volume resistivity is 1×10 12 Ω~1×10 15 Ω, a breakdown voltage between 2 kV and 50 kV, or a comparative tracking index value between 175 V and 400 V.

[0099] Example 16 is the method of any of the preceding or subsequent examples, wherein the tie layer comprises a first polyester film and the top polymer layer comprises a second polyester film having a different composition than the first polyester film.

[0100] Example 17 is a method of any of the preceding or subsequent examples, wherein the bonding layer includes a polymeric sealing layer exhibiting a first melting temperature, and the top polymeric layer exhibits a second melting temperature or decomposition temperature higher than the first melting temperature.

[0101] Example 18 is the method of any of the preceding or subsequent examples, wherein the first melting temperature is between 150°C and 250°C.

[0102] Example 19 is the method of any of the preceding or subsequent examples, wherein the top polymer layer comprises polyethylene, polypropylene, and / or polyethylene terephthalate.

[0103] Example 20 is the method of any preceding or subsequent example, wherein bonding comprises subjecting the multilayer polymeric insulation structure and the aluminum alloy sheet metal substrate to lamination conditions comprising exposure to a lamination temperature of from 175° C. to 300° C. and / or exposure to a lamination pressure of from 1 bar to 7 bar.

[0104] Example 21 is the method of any of the preceding or subsequent examples, further comprising annealing the bonded product at an annealing temperature between 175°C and 300°C.

[0105] Example 22 is a method of any preceding or subsequent example, wherein the multilayer polymer insulation structure is bonded to the surface of the aluminum alloy sheet metal substrate without the use of an adhesive layer between the aluminum alloy sheet metal substrate and the multilayer polymer insulation structure.

[0106] Example 23 is the method of any preceding or subsequent example, wherein no adhesive layer is disposed between the aluminum alloy sheet metal substrate and the multilayer polymeric insulation structure.

[0107] Example 24 is the method of any of the preceding or subsequent examples, wherein the bonding layer comprises an adhesion layer between the aluminum alloy sheet metal substrate and the top polymer layer.

[0108] Example 25 is the method of any of the preceding or subsequent examples, wherein the adhesion layer is disposed on the aluminum alloy sheet metal substrate prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer, or the adhesion layer is disposed on the top polymer layer prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer.

[0109] Example 26 is the method of any of the preceding or subsequent examples, wherein the aluminum alloy sheet metal substrate includes a surface pretreatment coating on an aluminum alloy sheet metal base layer.

[0110] Example 27 is the method of any of the preceding or subsequent examples, wherein the surface pretreatment coating comprises a Ti—Zr based conversion coating, a Cr based conversion coating, or a copolymer based coating.

[0111] Example 28 is a method according to any preceding or subsequent example, wherein the multilayer polymer insulation structure is bonded to the surface of the aluminum alloy sheet metal substrate without the use of an adhesive layer between the aluminum alloy sheet metal substrate and the multilayer polymer insulation structure.

[0112] Example 29 is the method of any preceding or subsequent example, further comprising subjecting the bonded product to one or more molding processes to produce a molded product.

[0113] Example 30 is the method of any of the preceding or subsequent examples, wherein the joint product is an electrically insulated metal product of any of the preceding or subsequent examples.

[0114] Example 31 is an electrically insulated metal product of any of the preceding or subsequent embodiments, prepared by a method of any of the preceding or subsequent embodiments.

[0115]

[0023] A thirty-second embodiment is a structural enclosure for a device, the structural enclosure comprising an electrically isolated metal fabrication comprising an aluminum alloy sheet metal substrate and a multilayer polymeric insulating structure bonded to the aluminum alloy sheet metal substrate, the multilayer polymeric insulating structure comprising a bonding layer adjacent to the aluminum alloy sheet metal substrate and a top polymer layer on the bonding layer, the multilayer polymeric insulating structure having a thickness of between 5 μm and 100 μm, and the multilayer polymeric insulating structure bonded to the aluminum alloy sheet metal substrate has an overall surface resistance of less than 1×10 12 Ω~1×10 15 Ω, volume resistivity is 1×10 12 Ω~1×10 15 Ω, a breakdown voltage of 2 kV to 50 kV, or a comparative tracking index value of 175 V to 400 V.

[0116] Example 33 is a structural enclosure of any preceding or subsequent example, comprising a plurality of said electrically insulated metal articles mechanically joined to one another.

[0117] Example 34 is the structural enclosure of any of the preceding or subsequent examples, wherein the electrically insulated metal article comprises an electrically insulated metal article of any of the preceding examples.

[0118] Example 35 is the structural enclosure of any of the preceding or subsequent examples, wherein the electrically insulated metal article is prepared by a method of any of the preceding or subsequent examples.

[0119] All patents and publications cited herein are incorporated by reference in their entirety. The foregoing description of the embodiments, including the illustrated embodiment, has been presented only for purposes of illustration and description and is not intended to be exhaustive or limited to the precise form disclosed. Numerous modifications, adaptations and uses thereof will be apparent to those skilled in the art.

Claims

1. An electrically insulated metal article, comprising: an aluminum alloy sheet metal substrate; and a multi-layer polymer insulating structure bonded to the aluminum alloy sheet metal substrate, the multi-layer polymer insulating structure including a bonding layer adjacent to the aluminum alloy sheet metal substrate and a top polymer layer on the bonding layer, the multi-layer polymer insulating structure having a thickness of 5 μm to 100 μm, and the multi-layer polymer insulating structure bonded to the aluminum alloy sheet metal substrate has an overall surface resistance of 1×10 １２ Ω~1×10 １５ Ω, volume resistance is 1×10 １２ Ω~1×10 １５ Ω, a breakdown voltage between 2 kV and 50 kV, or a comparative tracking index value between 175 V and 400 V.

2. 10. The electrically isolated metal product of claim 1, wherein the bonding layer comprises a first polyester film and the top polymer layer comprises a second polyester film having a different composition than the first polyester film.

3. 2. The electrically isolated metal article of claim 1, wherein the bonding layer comprises a polymer sealing layer exhibiting a first melting temperature, and the top polymer layer exhibits a second melting or decomposition temperature higher than the first melting temperature.

4. 4. The electrically insulated metal product of claim 3, wherein the first melting temperature is between 150°C and 250°C, or the polymer sealing layer is bonded to the aluminum alloy sheet metal substrate after preheating to between 150°C and 250°C.

5. 10. The electrically isolated metal article of claim 1, wherein the top polymer layer comprises polyethylene, polypropylene, and / or polyethylene terephthalate.

6. 2. The electrically insulated metal product of claim 1, wherein the multi-layer polymeric insulation structure is a laminated multi-layer film applied to the aluminum alloy sheet metal substrate under lamination conditions including exposure to a lamination temperature of 175°C to 300°C and / or exposure to a lamination pressure of 1 bar to 7 bar.

7. 10. The electrically isolated metal product of claim 1, wherein the multi-layer polymer insulating structure is an annealed multi-layer film subjected to annealing conditions of 175°C to 300°C.

8. 10. The electrically isolated metal article of claim 1, wherein no adhesive layer is disposed between said aluminum alloy sheet metal substrate and said multi-layer polymeric insulation structure.

9. 10. The electrically isolated metal article of claim 1, wherein the bonding layer comprises an adhesion layer between the aluminum alloy sheet metal substrate and the top polymer layer.

10. the adhesive layer is disposed on the aluminum alloy sheet metal substrate prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer; or 10. The electrically isolated metal article of claim 9, wherein the adhesive layer is disposed on the top polymer layer prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer.

11. 10. The electrically isolated metal article of claim 1, wherein said multi-layer polymeric insulation structure is free of pinholes or other defects that provide a conductive path to said aluminum alloy sheet metal substrate.

12. 10. The electrically isolated metal product of claim 1, wherein the aluminum alloy sheet metal substrate comprises a surface pretreatment coating on an aluminum alloy sheet metal base layer.

13. The electrically isolated metal product of claim 12, wherein the surface pretreatment coating comprises a Ti-Zr based conversion coating, a Cr based conversion coating, or a copolymer based coating.

14. 10. The electrically isolated metal article of claim 1, wherein the aluminum alloy sheet metal substrate has a non-planar shape or is in a formed configuration.

15. 1. A method for preparing an electrically insulated metal product, the method comprising: preheating an aluminum alloy sheet metal substrate to a first temperature of 150°C to 250°C; and bonding a multi-layer polymer insulating structure to a surface of the aluminum alloy sheet metal substrate to produce a bonded product, the multi-layer polymer insulating structure including a bonding layer and a top polymer layer on the bonding layer, the multi-layer polymer insulating structure having a thickness of 5 μm to 100 μm, and the multi-layer polymer insulating structure bonded to the aluminum alloy sheet metal substrate as a whole has a surface resistance of 1×10 １２ Ω~1×10 １５ Ω, volume resistance is 1×10 １２ Ω~1×10 １５ Ω, a breakdown voltage between 2 kV and 50 kV, or a comparative tracking index value between 175 V and 400 V.

16. 16. The method of claim 15, wherein the tie layer comprises a first polyester film and the top polymer layer comprises a second polyester film having a different composition than the first polyester film.

17. 16. The method of claim 15, wherein the bonding layer comprises a polymeric sealing layer exhibiting a first melting temperature and the top polymeric layer exhibits a second melting or decomposition temperature higher than the first melting temperature.

18. 18. The method of claim 17, wherein the first melting temperature is between 150°C and 250°C.

19. The method of claim 15 , wherein the top polymer layer comprises polyethylene, polypropylene, and / or polyethylene terephthalate.

20. 16. The method of claim 15, wherein bonding comprises subjecting the multi-layer polymeric insulation structure and the aluminum alloy sheet metal substrate to lamination conditions comprising exposure to a lamination temperature of 175°C to 300°C and / or exposure to a lamination pressure of 1 bar to 7 bar.

21. The method of claim 15, further comprising annealing the bonded product at an annealing temperature between 175°C and 300°C.

22. 16. The method of claim 15, wherein the multi-layer polymeric insulating structure is bonded to the surface of the aluminum alloy sheet metal substrate without the use of an adhesive layer between the aluminum alloy sheet metal substrate and the multi-layer polymeric insulating structure.

23. 16. The method of claim 15, wherein no adhesive layer is disposed between the aluminum alloy sheet metal substrate and the multi-layer polymeric insulating structure.

24. The method of claim 15 , wherein the bonding layer comprises an adhesion layer between the aluminum alloy sheet metal substrate and the top polymer layer.

25. the adhesive layer is disposed on the aluminum alloy sheet metal substrate prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer; or 25. The method of claim 24, wherein the adhesive layer is disposed on the top polymer layer prior to bonding the aluminum alloy sheet metal substrate to the top polymer layer.

26. 16. The method of claim 15, wherein the aluminum alloy sheet metal substrate comprises a surface pretreatment coating on an aluminum alloy sheet metal base layer.

27. The method of claim 26, wherein the surface pretreatment coating comprises a Ti-Zr based conversion coating, a Cr based conversion coating, or a copolymer based coating.

28. The method of claim 15, further comprising subjecting the bonded product to one or more molding processes to produce a molded product.

29. The method according to any of claims 15 to 28, wherein the joint product is an electrically insulated metal product according to any of claims 1 to 14.

30. An electrically insulated metal product according to any one of claims 1 to 14, prepared by a method according to any one of claims 15 to 28.

31. 1. A structural enclosure for a device, the structural enclosure comprising: and an electrically insulated metal article, the electrically insulated metal article comprising: an aluminum alloy sheet metal substrate; and a multi-layer polymer insulating structure bonded to the aluminum alloy sheet metal substrate, the multi-layer polymer insulating structure including a bonding layer adjacent to the aluminum alloy sheet metal substrate and a top polymer layer on the bonding layer, the multi-layer polymer insulating structure having a thickness of 5 μm to 100 μm, and the multi-layer polymer insulating structure bonded to the aluminum alloy sheet metal substrate has an overall surface resistance of 1×10 １２ Ω~1×10 １５ Ω, volume resistance is 1×10 １２ Ω~1×10 １５ Ω, a breakdown voltage between 2 kV and 50 kV, or a comparative tracking index value between 175 V and 400 V.

32. 32. The structural enclosure of claim 31 comprising a plurality of electrically insulated metal fabrications mechanically joined to one another.

33. 32. The structural enclosure of claim 31, wherein the electrically insulating metal article comprises an electrically insulating metal article according to any of claims 1-14.

34. 32. The structural enclosure of claim 31, wherein the electrically insulated metal product is prepared by a method according to any one of claims 15 to 28.

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